# Grammar production rules to generate univariate expression without
# coefficients and with one constant 1.
# Introducing constant 1 can enable more variations in the asymptotic behavior.
# For example, 1 / x has leading power -1 at both 0 and inf. However, by simple
# modification, 1 / ( 1 + x ) will have leading power -1 at inf but leading
# power 0 at 0.
S -> S '+' T
S -> S '-' T
S -> S '*' T
S -> S '/' T
S -> T
T -> '(' S ')'
T -> 'x'
T -> '1'
